2ZQZ:
reference: Active and inactive state structures of unliganded Lactobacillus casei allosteric L-lactate dehydrogenase., Arai K, Ishimitsu T, Fushinobu S, Uchikoba H, Matsuzawa H, Taguchi H, Proteins. 2010 Feb 15;78(3):681-94. PMID: 19787773

This OCA Structure page
uses Jmol, developed by the Jmol Development Team (documentation).